Monitoring Health Inequities and Planning in Virginia: Poverty, Human Immunodeficiency Virus, and Sexually Transmitted Infections

Abstract

Monitoring social inequalities in sexual health is important to the effective allocation of resources for human immunodeficiency virus (HIV) and sexually transmitted infection (STI) prevention by state health departments and other outside planning groups. At the Virginia Department of Health, like most US public health agencies, there is a lack of consistent socioeconomic data, such as individual-level poverty measures, collected through routine disease surveillance.1 As a result, state epidemiologists are only able to provide a general description of poverty, such as the percentage of people living in poverty while providing HIV/STI rates for the same administrative area.2–8 This article has 2 objectives. The first is to quantify and compare HIV/STI incidence across 4 stratum of poverty at the census tract level in Virginia using methods developed by the Public Health Disparities Geocoding Project.9 Second, for each poverty strata we examine the distribution of HIV-positive and other high-risk populations, identified as priority concerns for HIV prevention planning in Virginia (“priority populations”). This research can help epidemiologists and outside planning groups, who often lack access to geocoded data guide resource allocation for HIV/STI prevention. The Public Health Disparities Geocoding Project helps facilitate routine monitoring of health inequities in the United States by providing epidemiologists with an established statistical framework for comparing disease rates at the census tract level to a census tract-based measure of poverty.9 The methodology for monitoring socioeconomic inequalities through quantifying the relationship between infection rates and area-based socioeconomic measures (ABSM) was developed and is described by the Public Health Disparities Geocoding Project. Briefly, outcomes were geocoded to the census tract level, tracts were stratified into discrete poverty levels (0%– 4.9%, 5.0%–9.9%, 10.0%–19.99%, and 20%–100% population living below poverty), age-standardized incidence rates were calculated for each stratum of poverty, and 95% confidence intervals based on the distribution were calculated.9 To calculate infection rates at the census tract level, we geocoded clinically diagnosed cases of HIV [regardless of transition to acquired immune deficiency syndrome (AIDS)], chlamydia (CT), gonorrhea (NG), and total early syphilis (TES) between 2000 and 2005 using addresses obtained from Virginia’s HIV and AIDS Reporting System (HARS) and the STD Management Information System (STDMIS). Geocoding was performed with Centrus Geostan.10 Each census tract in Virginia was stratified into 1 of 4 discrete poverty stratum, which are defined by an area-based socioeconomic measure created by the Public Health Disparities Geocoding Project from 2000 census data.11 Each stratum is an aggregation of census tracts based on the percentage of the tract’s total population living below the federal poverty line. Four hundred eighty (31%), 428 (28%), 418 (27%), and 206 (13%) census tracts were assigned to the 0% to 4.9%, 5.0% to 9.9%, 10.0% to 19.9%, and 20.0% to 100% stratum, respectively. Age-standardized incidence rates and incidence rate ratios (IRRs) for each disease were calculated for each stratum of poverty, and 95% confidence intervals based on the distribution were calculated. Gamma intervals are commonly used when the outcomes are directly standardized rates and a small number of cases and a large variability in weights exists.12 Addresses were considered geocodable to the census tract level if they geocoded to a street/house/intersection, the center of a block group/census tract or the center of a zip code, where The authors wish to thank Rene Cabral-Daniels, Jason Carr, Jeanette Gustat, Hongjie Liu and Jeff Stover, for their careful review of the manuscript. This activity was conducted, in part, through the support of the Centers for Disease Control and Prevention (CDC) Cooperative Agreement No. U62-PS000559, “Evaluating Integration of HIV/AIDS Surveillance Data with a Geographic Information System.” Additional support was provided through ongoing collaborative activities associated with the Outcomes Assessment through Systems of Integrated Surveillance (OASIS) workgroup, which was a CDC funded activity from 1998 through 2005. The Health Informatics and Integrated Surveillance Systems staff within the Virginia Department of Health-Division of Disease Prevention are grateful for the impetus OASIS had on our geographic information systems initiatives, our analytical infrastructure and our public health network of colleagues. Correspondence: Carrie Dolan, MPH, 5308 Discovery Park Building, Suite 101, Williamsburg, VA 23188. E-mail: cdolan@wchf.com. Received for publication August 30, 2007, and accepted June 7, 2008. From the Division of Disease Prevention, Virginia Department of Health, Richmond, Virginia Sexually Transmitted Diseases, December 2008, Vol. 35, No. 12, p.981–984 DOI: 10.1097/OLQ.0b013e318182a571 Copyright © 2008, American Sexually Transmitted Diseases Association All rights reserved.